For the benefit of other readers this is a Progressive Industries Surge Suppressor.
60Hz is the frequency of the AC line. Power from the US national grid will always be exactly 60 cycles per second. When you are getting power from a stand alone generator, the frequency may not be stable.
L-1 is indeed line one one of the two live 120 nominal lines
124 is the RMS voltage. 125 is the high target voltage 110 is low.
2A is the current draw in amps on L-1 probably a light charge from the converter to supply the 12V
L-2 is indeed line 2
125 the voltage, Note L-2 Voltage is 180 degrees out of phase of L-1
2A the current draw on L-2 probably powering the refrigerator.